1<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.01//EN" "http://www.w3.org/TR/html4/strict.dtd"> 2<html> 3 <head> 4 <link rel="stylesheet" type="text/css" href="opus_in_isobmff.css"/> 5 <meta http-equiv="Content-Type" content="text/html; charset=utf-8" /> 6 <title>Encapsulation of Opus in ISO Base Media File Format</title> 7 </head> 8 <body bgcolor="0x333333" text="#60B0C0"> 9 <b><u>Encapsulation of Opus in ISO Base Media File Format</u></b><br> 10 <font size="2">last updated: April 28, 2016</font><br> 11 <br> 12 <div class="normal_link pre frame_box"> 13 14 Encapsulation of Opus in ISO Base Media File Format 15 Version 0.6.8 (incomplete) 16 17 18Table of Contents 19<a href="#1">1</a> Scope 20<a href="#2">2</a> Normative References 21<a href="#3">3</a> Terms and Definitions 22<a href="#4">4</a> Design Rules of Encapsulation 23 <a href="#4.1">4.1</a> File Type Indentification 24 <a href="#4.2">4.2</a> Overview of Track Structure 25 <a href="#4.3">4.3</a> Definitions of Opus sample 26 <a href="#4.3.1">4.3.1</a> Sample entry format 27 <a href="#4.3.2">4.3.2</a> Opus Specific Box 28 <a href="#4.3.3">4.3.3</a> Sample format 29 <a href="#4.3.4">4.3.4</a> Duration of Opus sample 30 <a href="#4.3.5">4.3.5</a> Sub-sample 31 <a href="#4.3.6">4.3.6</a> Random Access 32 <a href="#4.3.6.1">4.3.6.1</a> Random Access Point 33 <a href="#4.3.6.2">4.3.6.2</a> Pre-roll 34 <a href="#4.4">4.4</a> Trimming of Actual Duration 35 <a href="#4.5">4.5</a> Channel Layout (informative) 36 <a href="#4.6">4.6</a> Basic Structure (informative) 37 <a href="#4.6.1">4.6.2</a> Initial Movie 38 <a href="#4.6.2">4.6.3</a> Movie Fragments 39 <a href="#4.7">4.7</a> Example of Encapsulation (informative) 40<a href="#5">5</a> Author's Address 41 42<a name="1"></a> 431 Scope 44 This specification specifies the fundamental way of the encapsulation of Opus coded bitstreams in ISO Base Media 45 file format and its derivatives. The encapsulation of Opus coded bitstreams in QuickTime file format is outside 46 the scope of this specification. 47 48<a name="2"></a> 492 Normative References 50 [1] ISO/IEC 14496-12:2015 Corrected version 51 Information technology — Coding of audio-visual objects — Part 12: ISO base media file format 52 53 [2] RFC 6716 54 Definition of the Opus Audio Codec 55 56 [3] draft-ietf-codec-oggopus-06 57 Ogg Encapsulation for the Opus Audio Codec 58 59<a name="3"></a> 603 Terms and Definitions 61 3.1 active track 62 enabled track from the non-alternate group or selected track from alternate group 63 64 3.2 actual duration 65 duration constructed from valid samples 66 67 3.3 edit 68 entry in the Edit List Box 69 70 3.4 padded samples 71 PCM samples after decoding Opus sample(s) which are not valid samples 72 An Opus bitstream always contains them partially at the beginning and may contain them in part at the end, as 73 long as not physically removed yet at the beginning and/or the end. 74 75 3.5 priming samples 76 padded samples at the beginning of the Opus bitstream 77 78 3.6 sample-accurate 79 for any PCM sample, a timestamp exactly matching its sampling timestamp is present in the media timeline. 80 81 3.7 valid samples 82 PCM samples after decoding Opus sample(s) corresponding to input PCM samples 83 84<a name="4"></a> 854 Design Rules of Encapsulation 86 4.1 File Type Indentification<a name="4.1"></a> 87 This specification does not define any brand to declare files are conformant to this specification. However, 88 files conformant to this specification shall contain at least one brand, which supports the requirements and the 89 requirements described in this clause without contradiction, in the compatible brands list of the File Type Box. 90 As an example, the minimal support of the encapsulation of Opus bitstreams in ISO Base Media file format requires 91 the 'iso2' brand in the compatible brands list since support of roll groups is required. 92<a name="4.2"></a> 93 4.2 Overview of Track Structure 94 This clause summarizes requirements of the encapsulation of Opus coded bitstream as media data in audio tracks 95 in file formats compliant with the ISO Base Media File Format. The details are described in clauses after this 96 clause. 97 + The handler_type field in the Handler Reference Box shall be set to 'soun'. 98 + The Media Information Box shall contain the Sound Media Header Box. 99 + The codingname of the sample entry is 'Opus'. 100 This specification does not define any encapsulation using MP4AudioSampleEntry with objectTypeIndication 101 specified by the MPEG-4 Registration Authority (http://www.mp4ra.org/). 102 See 4.3.1 Sample entry format to get the details about the sample entry. 103 + The 'dOps' box is added to the sample entry to convey initializing information for the decoder. 104 See 4.3.2 Opus Specific Box to get the details. 105 + An Opus sample is exactly one Opus packet for each of different Opus bitstreams. 106 See 4.3.3 Sample format to get the details. 107 + Every Opus sample is a sync sample but requires pre-roll for every random access to get correct output. 108 See 4.3.6 Random Access to get the details. 109<a name="4.3"></a> 110 4.3 Definitions of Opus sample 111 4.3.1 Sample entry format<a name="4.3.1"></a> 112 For any track containing Opus bitstreams, at least one sample entry describing corresponding Opus bitstream 113 shall be present inside the Sample Table Box. This version of the specification defines only one sample 114 entry format named OpusSampleEntry whose codingname is 'Opus'. This sample entry includes exactly one Opus 115 Specific Box defined in 4.3.2 as a mandatory box and indicates that Opus samples described by this sample 116 entry are stored by the sample format described in 4.3.3. 117 118 The syntax and semantics of the OpusSampleEntry is shown as follows. 119 120 class OpusSampleEntry() extends AudioSampleEntry ('Opus'){ 121 OpusSpecificBox(); 122 } 123 124 + channelcount: 125 The channelcount field shall be set to the sum of the total number of Opus bitstreams and the number 126 of Opus bitstreams producing two channels. This value is indentical with (M+N), where M is the value of 127 the *Coupled Stream Count* field and N is the value of the *Stream Count* field in the *Channel Mapping 128 Table* in the identification header defined in Ogg Opus [3]. 129 + samplesize: 130 The samplesize field shall be set to 16. 131 + samplerate: 132 The samplerate field shall be set to 48000<<16. 133 + OpusSpecificBox 134 This box contains initializing information for the decoder as defined in 4.3.2. 135 136 4.3.2 Opus Specific Box<a name="4.3.2"></a> 137 Exactly one Opus Specific Box shall be present in each OpusSampleEntry. 138 The Opus Specific Box contains the Version field and this specification defines version 0 of this box. 139 If incompatible changes occured in the fields after the Version field within the OpusSpecificBox in the 140 future versions of this specification, another version will be defined. 141 This box refers to Ogg Opus [3] at many parts but all the data are stored as big-endian format. 142 143 The syntax and semantics of the Opus Specific Box is shown as follows. 144 145 class ChannelMappingTable (unsigned int(8) OutputChannelCount){ 146 unsigned int(8) StreamCount; 147 unsigned int(8) CoupledCount; 148 unsigned int(8 * OutputChannelCount) ChannelMapping; 149 } 150 151 aligned(8) class OpusSpecificBox extends Box('dOps'){ 152 unsigned int(8) Version; 153 unsigned int(8) OutputChannelCount; 154 unsigned int(16) PreSkip; 155 unsigned int(32) InputSampleRate; 156 signed int(16) OutputGain; 157 unsigned int(8) ChannelMappingFamily; 158 if (ChannelMappingFamily != 0) { 159 ChannelMappingTable(OutputChannelCount); 160 } 161 } 162 163 + Version: 164 The Version field shall be set to 0. 165 In the future versions of this specification, this field may be set to other values. And without support 166 of those values, the reader shall not read the fields after this within the OpusSpecificBox. 167 + OutputChannelCount: 168 The OutputChannelCount field shall be set to the same value as the *Output Channel Count* field in the 169 identification header defined in Ogg Opus [3]. 170 + PreSkip: 171 The PreSkip field indicates the number of the priming samples, that is, the number of samples at 48000 Hz 172 to discard from the decoder output when starting playback. The value of the PreSkip field shall be at least 173 80 milliseconds' worth of PCM samples even when removing any number of Opus samples which may or may not 174 contain the priming samples. The PreSkip field is not used for discarding the priming samples at the whole 175 playback at all since it is informative only, and that task falls on the Edit List Box. 176 + InputSampleRate: 177 The InputSampleRate field shall be set to the same value as the *Input Sample Rate* field in the 178 identification header defined in Ogg Opus [3]. 179 + OutputGain: 180 The OutputGain field shall be set to the same value as the *Output Gain* field in the identification 181 header define in Ogg Opus [3]. Note that the value is stored as 8.8 fixed-point. 182 + ChannelMappingFamily: 183 The ChannelMappingFamily field shall be set to the same value as the *Channel Mapping Family* field in 184 the identification header defined in Ogg Opus [3]. 185 + StreamCount: 186 The StreamCount field shall be set to the same value as the *Stream Count* field in the identification 187 header defined in Ogg Opus [3]. 188 + CoupledCount: 189 The CoupledCount field shall be set to the same value as the *Coupled Count* field in the identification 190 header defined in Ogg Opus [3]. 191 + ChannelMapping: 192 The ChannelMapping field shall be set to the same octet string as *Channel Mapping* field in the identi- 193 fication header defined in Ogg Opus [3]. 194 195 4.3.3 Sample format<a name="4.3.3"></a> 196 An Opus sample is exactly one Opus packet for each of different Opus bitstreams. Due to support more than 197 two channels, an Opus sample can contain frames from multiple Opus bitstreams but all Opus packets shall 198 share with the total of frame sizes in a single Opus sample. The way of how to pack an Opus packet from 199 each of Opus bitstreams into a single Opus sample follows Appendix B. in RFC 6716 [2]. 200 The endianness has nothing to do with any Opus sample since every Opus packet is processed byte-by-byte. 201 In this specification, 'sample' means 'Opus sample' except for 'padded samples', 'priming samples', 'valid 202 sample' and 'sample-accurate', i.e. 'sample' is 'sample' in the term defined in ISO/IEC 14496-12 [1]. 203 204 +-----------------------------------------+-------------------------------------+ 205 | Opus packet 0 (self-delimiting framing) | Opus packet 1 (undelimited framing) | 206 +-----------------------------------------+-------------------------------------+ 207 |<---------------------------- the size of Opus sample ------------------------>| 208 209 Figure 1 - Example structure of an Opus sample containing two Opus bitstreams 210 211 4.3.4 Duration of Opus sample<a name="4.3.4"></a> 212 The duration of Opus sample is given by multiplying the total of frame sizes for a single Opus bitstream 213 expressed in seconds by the value of the timescale field in the Media Header Box. 214 Let's say an Opus sample consists of two Opus bitstreams, where the frame size of one bitstream is 40 milli- 215 seconds and the frame size of another is 60 milliseconds, and the timescale field in the Media Header Box 216 is set to 48000, then the duration of that Opus sample shall be 120 milliseconds since three 40 millisecond 217 frame and two 60 millisecond frames shall be contained because of the maximum duration of Opus packet, 120 218 milliseconds, and 5760 in the timescale indicated in the Media Header Box. 219 220 To indicate the valid samples excluding the padded samples at the end of Opus bitstream, the duration of 221 the last Opus sample of an Opus bitstream is given by multiplying the number of the valid samples by the 222 value produced by dividing the value of the timescale field in the Media Header Box by 48000. 223 224 4.3.5 Sub-sample<a name="4.3.5"></a> 225 The structure of the last Opus packet in an Opus sample is different from the others in the same Opus sample, 226 and the others are invalid Opus packets as an Opus sample because of self-delimiting framing. To avoid 227 complexities, sub-sample is not defined for Opus sample in this specification. 228 229 4.3.6 Random Access<a name="4.3.6"></a> 230 This subclause describes the nature of the random access of Opus sample. 231 232 4.3.6.1 Random Access Point<a name="4.3.6.1"></a> 233 All Opus samples can be independently decoded i.e. every Opus sample is a sync sample. Therefore, the 234 Sync Sample Box shall not be present as long as there are no samples other than Opus samples in the same 235 track. And the sample_is_non_sync_sample field for Opus samples shall be set to 0. 236 237 4.3.6.2 Pre-roll<a name="4.3.6.2"></a> 238 Opus bitstream requires at least 80 millisecond pre-roll after each random access to get correct output. 239 Pre-roll is indicated by the roll_distance field in AudioRollRecoveryEntry. AudioPreRollEntry shall not 240 be used since every Opus sample is a sync sample in Opus bitstream. Note that roll_distance is expressed 241 in sample units in a term of ISO Base Media File Format, and always takes negative values. 242 243 For any track containing Opus bitstreams, at least one Sample Group Description Box and at least one 244 Sample to Group Box within the Sample Table Box shall be present and these have the grouping_type field 245 set to 'roll'. If any Opus sample is contained in a track fragment, the Sample to Group Box with the 246 grouping_type field set to 'roll' shall be present for that track fragment. 247 248 For the requirement of AudioRollRecoveryEntry, the compatible_brands field in the File Type Box shall 249 contain at least one brand which requires support for roll groups. 250<a name="4.4"></a> 251 4.4 Trimming of Actual Duration 252 Due to the priming samples (or the padding at the beginning) derived from the pre-roll for the startup and the 253 padded samples at the end, we need trim from media to get the actual duration. An edit in the Edit List Box can 254 achieve this demand, and the Edit Box and the Edit List Box shall be present. 255 256 For sample-accurate trimming, proper timescale should be set to the timescale field in the Movie Header Box 257 and the Media Header Box inside Track Box(es) for Opus bitstream. The timescale field in the Media Header Box is 258 typically set to 48000. It is recommended that the timescale field in the Movie Header Box be set to the same 259 value of the timescale field in the Media Header Box in order to avoid the rounding problem when specifying 260 duration of edit if the timescales in all of the Media Header Boxes are set to the same value. 261 262 For example, to indicate the actual duration of an Opus bitstream in a track with the timescale fields of both 263 the Movie Header Box and the Media Header Box set to 48000, we would use the following edit: 264 segment_duration = the number of the valid samples 265 media_time = the number of the priming samples 266 media_rate = 1 << 16 267 268 The Edit List Box is applied to whole movie including all movie fragments. Therefore, it is impossible to tell 269 the actual duration in the case producing movie fragments on the fly such as live-streaming. In such cases, 270 the duration of the last Opus sample may be helpful by setting zero to the segment_duration field since the 271 value 0 represents implicit duration equal to the sum of the duration of all samples. 272<a name="4.5"></a> 273 4.5 Channel Layout (informative) 274 By the application of alternate_group in the Track Header Box, whole audio channels in all active tracks from 275 non-alternate group and/or different alternate group from each other are composited into the presentation. If 276 an Opus sample consists of multiple Opus bitstreams, it can be splitted into individual Opus bitstreams and 277 reconstructed into new Opus samples as long as every Opus bitstream has the same total duration in each Opus 278 sample. This nature can be utilized to encapsulate a single Opus bitstream in each track without breaking the 279 original channel layout. 280 281 As an example, let's say there is a following track: 282 OutputChannelCount = 6; 283 StreamCount = 4; 284 CoupledCount = 2; 285 ChannelMapping = {0, 4, 1, 2, 3, 5}; // front left, front center, front right, rear left, rear right, LFE 286 Here, to couple front left to front right channels into the first stream, and couple rear left to rear right 287 channels into the second stream, reordering is needed since coupled streams must precede any non-coupled stream. 288 You extract the four Opus bitstreams from this track and you encapsulate two of the four into a track and the 289 others into another track. The former track is as follows. 290 OutputChannelCount = 6; 291 StreamCount = 2; 292 CoupledCount = 2; 293 ChannelMapping = {0, 255, 1, 2, 3, 255}; // front left, front center, front right, rear left, rear right, LFE 294 And the latter track is as follows. 295 OutputChannelCount = 6; 296 StreamCount = 2; 297 CoupledCount = 0; 298 ChannelMapping = {255, 0, 255, 255, 255, 1}; // front left, front center, front right, rear left, rear right, LFE 299 In addition, the value of the alternate_group field in the both tracks is set to 0. As the result, the player 300 may play as if channels with 255 are not present, and play the presentation constructed from the both tracks 301 in the same channel layout as the one of the original track. Keep in mind that the way of the composition, i.e. 302 the mixing for playback, is not defined here, and maybe different results could occur except for the channel 303 layout of the original, depending on an implementation or the definition of a derived file format. 304 305 Note that some derived file formats may specify the restriction to ignore alternate grouping. In the context of 306 such file formats, this application is not available. This unavailability does not mean incompatibilities among 307 file formats unless the restriction to the value of the alternate_group field is specified and brings about 308 any conflict among their definitions. 309<a name="4.6"></a> 310 4.6 Basic Structure (informative) 311 4.6.1 Initial Movie<a name="4.6.1"></a> 312 This subclause shows a basic structure of the Movie Box as follows: 313 314 +----+----+----+----+----+----+----+----+------------------------------+ 315 |moov| | | | | | | | Movie Box | 316 +----+----+----+----+----+----+----+----+------------------------------+ 317 | |mvhd| | | | | | | Movie Header Box | 318 +----+----+----+----+----+----+----+----+------------------------------+ 319 | |trak| | | | | | | Track Box | 320 +----+----+----+----+----+----+----+----+------------------------------+ 321 | | |tkhd| | | | | | Track Header Box | 322 +----+----+----+----+----+----+----+----+------------------------------+ 323 | | |edts| | | | | | Edit Box | 324 +----+----+----+----+----+----+----+----+------------------------------+ 325 | | | |elst| | | | | Edit List Box | 326 +----+----+----+----+----+----+----+----+------------------------------+ 327 | | |mdia| | | | | | Media Box | 328 +----+----+----+----+----+----+----+----+------------------------------+ 329 | | | |mdhd| | | | | Media Header Box | 330 +----+----+----+----+----+----+----+----+------------------------------+ 331 | | | |hdlr| | | | | Handler Reference Box | 332 +----+----+----+----+----+----+----+----+------------------------------+ 333 | | | |minf| | | | | Media Information Box | 334 +----+----+----+----+----+----+----+----+------------------------------+ 335 | | | | |smhd| | | | Sound Media Header Box | 336 +----+----+----+----+----+----+----+----+------------------------------+ 337 | | | | |dinf| | | | Data Information Box | 338 +----+----+----+----+----+----+----+----+------------------------------+ 339 | | | | | |dref| | | Data Reference Box | 340 +----+----+----+----+----+----+----+----+------------------------------+ 341 | | | | | | |url | | DataEntryUrlBox | 342 +----+----+----+----+----+----+ or +----+------------------------------+ 343 | | | | | | |urn | | DataEntryUrnBox | 344 +----+----+----+----+----+----+----+----+------------------------------+ 345 | | | | |stbl| | | | Sample Table | 346 +----+----+----+----+----+----+----+----+------------------------------+ 347 | | | | | |stsd| | | Sample Description Box | 348 +----+----+----+----+----+----+----+----+------------------------------+ 349 | | | | | | |Opus| | OpusSampleEntry | 350 +----+----+----+----+----+----+----+----+------------------------------+ 351 | | | | | | | |dOps| Opus Specific Box | 352 +----+----+----+----+----+----+----+----+------------------------------+ 353 | | | | | |stts| | | Decoding Time to Sample Box | 354 +----+----+----+----+----+----+----+----+------------------------------+ 355 | | | | | |stsc| | | Sample To Chunk Box | 356 +----+----+----+----+----+----+----+----+------------------------------+ 357 | | | | | |stsz| | | Sample Size Box | 358 +----+----+----+----+----+ or +----+----+------------------------------+ 359 | | | | | |stz2| | | Compact Sample Size Box | 360 +----+----+----+----+----+----+----+----+------------------------------+ 361 | | | | | |stco| | | Chunk Offset Box | 362 +----+----+----+----+----+ or +----+----+------------------------------+ 363 | | | | | |co64| | | Chunk Large Offset Box | 364 +----+----+----+----+----+----+----+----+------------------------------+ 365 | | | | | |sgpd| | | Sample Group Description Box | 366 +----+----+----+----+----+----+----+----+------------------------------+ 367 | | | | | |sbgp| | | Sample to Group Box | 368 +----+----+----+----+----+----+----+----+------------------------------+ 369 | |mvex|* | | | | | | Movie Extends Box | 370 +----+----+----+----+----+----+----+----+------------------------------+ 371 | | |trex|* | | | | | Track Extends Box | 372 +----+----+----+----+----+----+----+----+------------------------------+ 373 374 Figure 2 - Basic structure of Movie Box 375 376 It is strongly recommended that the order of boxes should follow the above structure. 377 Boxes marked with an asterisk (*) may be present. 378 For most boxes listed above, the definition is as is defined in ISO/IEC 14496-12 [1]. The additional boxes 379 and the additional requirements, restrictions and recommendations to the other boxes are described in this 380 specification. 381 382 4.6.2 Movie Fragments<a name="4.6.2"></a> 383 This subclause shows a basic structure of the Movie Fragment Box as follows: 384 385 +----+----+----+----+----+----+----+----+------------------------------+ 386 |moof| | | | | | | | Movie Fragment Box | 387 +----+----+----+----+----+----+----+----+------------------------------+ 388 | |mfhd| | | | | | | Movie Fragment Header Box | 389 +----+----+----+----+----+----+----+----+------------------------------+ 390 | |traf| | | | | | | Track Fragment Box | 391 +----+----+----+----+----+----+----+----+------------------------------+ 392 | | |tfhd| | | | | | Track Fragment Header Box | 393 +----+----+----+----+----+----+----+----+------------------------------+ 394 | | |trun| | | | | | Track Fragment Run Box | 395 +----+----+----+----+----+----+----+----+------------------------------+ 396 | | |sgpd|* | | | | | Sample Group Description Box | 397 +----+----+----+----+----+----+----+----+------------------------------+ 398 | | |sbgp|* | | | | | Sample to Group Box | 399 +----+----+----+----+----+----+----+----+------------------------------+ 400 401 Figure 3 - Basic structure of Movie Fragment Box 402 403 It is strongly recommended that the Movie Fragment Header Box and the Track Fragment Header Box be 404 placed first in their container. 405 Boxes marked with an asterisk (*) may be present. 406 For the boxes listed above, the definition is as is defined in ISO/IEC 14496-12 [1]. 407<a name="4.7"></a> 408 4.7 Example of Encapsulation (informative) 409 [File] 410 size = 17790 411 [ftyp: File Type Box] 412 position = 0 413 size = 24 414 major_brand = mp42 : MP4 version 2 415 minor_version = 0 416 compatible_brands 417 brand[0] = mp42 : MP4 version 2 418 brand[1] = iso2 : ISO Base Media file format version 2 419 [moov: Movie Box] 420 position = 24 421 size = 757 422 [mvhd: Movie Header Box] 423 position = 32 424 size = 108 425 version = 0 426 flags = 0x000000 427 creation_time = UTC 2014/12/12, 18:41:19 428 modification_time = UTC 2014/12/12, 18:41:19 429 timescale = 48000 430 duration = 33600 (00:00:00.700) 431 rate = 1.000000 432 volume = 1.000000 433 reserved = 0x0000 434 reserved = 0x00000000 435 reserved = 0x00000000 436 transformation matrix 437 | a, b, u | | 1.000000, 0.000000, 0.000000 | 438 | c, d, v | = | 0.000000, 1.000000, 0.000000 | 439 | x, y, w | | 0.000000, 0.000000, 1.000000 | 440 pre_defined = 0x00000000 441 pre_defined = 0x00000000 442 pre_defined = 0x00000000 443 pre_defined = 0x00000000 444 pre_defined = 0x00000000 445 pre_defined = 0x00000000 446 next_track_ID = 2 447 [iods: Object Descriptor Box] 448 position = 140 449 size = 33 450 version = 0 451 flags = 0x000000 452 [tag = 0x10: MP4_IOD] 453 expandableClassSize = 16 454 ObjectDescriptorID = 1 455 URL_Flag = 0 456 includeInlineProfileLevelFlag = 0 457 reserved = 0xf 458 ODProfileLevelIndication = 0xff 459 sceneProfileLevelIndication = 0xff 460 audioProfileLevelIndication = 0xfe 461 visualProfileLevelIndication = 0xff 462 graphicsProfileLevelIndication = 0xff 463 [tag = 0x0e: ES_ID_Inc] 464 expandableClassSize = 4 465 Track_ID = 1 466 [trak: Track Box] 467 position = 173 468 size = 608 469 [tkhd: Track Header Box] 470 position = 181 471 size = 92 472 version = 0 473 flags = 0x000007 474 Track enabled 475 Track in movie 476 Track in preview 477 creation_time = UTC 2014/12/12, 18:41:19 478 modification_time = UTC 2014/12/12, 18:41:19 479 track_ID = 1 480 reserved = 0x00000000 481 duration = 33600 (00:00:00.700) 482 reserved = 0x00000000 483 reserved = 0x00000000 484 layer = 0 485 alternate_group = 0 486 volume = 1.000000 487 reserved = 0x0000 488 transformation matrix 489 | a, b, u | | 1.000000, 0.000000, 0.000000 | 490 | c, d, v | = | 0.000000, 1.000000, 0.000000 | 491 | x, y, w | | 0.000000, 0.000000, 1.000000 | 492 width = 0.000000 493 height = 0.000000 494 [edts: Edit Box] 495 position = 273 496 size = 36 497 [elst: Edit List Box] 498 position = 281 499 size = 28 500 version = 0 501 flags = 0x000000 502 entry_count = 1 503 entry[0] 504 segment_duration = 33600 505 media_time = 312 506 media_rate = 1.000000 507 [mdia: Media Box] 508 position = 309 509 size = 472 510 [mdhd: Media Header Box] 511 position = 317 512 size = 32 513 version = 0 514 flags = 0x000000 515 creation_time = UTC 2014/12/12, 18:41:19 516 modification_time = UTC 2014/12/12, 18:41:19 517 timescale = 48000 518 duration = 34560 (00:00:00.720) 519 language = und 520 pre_defined = 0x0000 521 [hdlr: Handler Reference Box] 522 position = 349 523 size = 51 524 version = 0 525 flags = 0x000000 526 pre_defined = 0x00000000 527 handler_type = soun 528 reserved = 0x00000000 529 reserved = 0x00000000 530 reserved = 0x00000000 531 name = Xiph Audio Handler 532 [minf: Media Information Box] 533 position = 400 534 size = 381 535 [smhd: Sound Media Header Box] 536 position = 408 537 size = 16 538 version = 0 539 flags = 0x000000 540 balance = 0.000000 541 reserved = 0x0000 542 [dinf: Data Information Box] 543 position = 424 544 size = 36 545 [dref: Data Reference Box] 546 position = 432 547 size = 28 548 version = 0 549 flags = 0x000000 550 entry_count = 1 551 [url : Data Entry Url Box] 552 position = 448 553 size = 12 554 version = 0 555 flags = 0x000001 556 location = in the same file 557 [stbl: Sample Table Box] 558 position = 460 559 size = 321 560 [stsd: Sample Description Box] 561 position = 468 562 size = 79 563 version = 0 564 flags = 0x000000 565 entry_count = 1 566 [Opus: Audio Description] 567 position = 484 568 size = 63 569 reserved = 0x000000000000 570 data_reference_index = 1 571 reserved = 0x0000 572 reserved = 0x0000 573 reserved = 0x00000000 574 channelcount = 6 575 samplesize = 16 576 pre_defined = 0 577 reserved = 0 578 samplerate = 48000.000000 579 [dOps: Opus Specific Box] 580 position = 520 581 size = 27 582 Version = 0 583 OutputChannelCount = 6 584 PreSkip = 312 585 InputSampleRate = 48000 586 OutputGain = 0 587 ChannelMappingFamily = 1 588 StreamCount = 4 589 CoupledCount = 2 590 ChannelMapping 591 0 -> 0: front left 592 1 -> 4: fron center 593 2 -> 1: front right 594 3 -> 2: side left 595 4 -> 3: side right 596 5 -> 5: rear center 597 [stts: Decoding Time to Sample Box] 598 position = 547 599 size = 24 600 version = 0 601 flags = 0x000000 602 entry_count = 1 603 entry[0] 604 sample_count = 18 605 sample_delta = 1920 606 [stsc: Sample To Chunk Box] 607 position = 571 608 size = 40 609 version = 0 610 flags = 0x000000 611 entry_count = 2 612 entry[0] 613 first_chunk = 1 614 samples_per_chunk = 13 615 sample_description_index = 1 616 entry[1] 617 first_chunk = 2 618 samples_per_chunk = 5 619 sample_description_index = 1 620 [stsz: Sample Size Box] 621 position = 611 622 size = 92 623 version = 0 624 flags = 0x000000 625 sample_size = 0 (variable) 626 sample_count = 18 627 entry_size[0] = 977 628 entry_size[1] = 938 629 entry_size[2] = 939 630 entry_size[3] = 938 631 entry_size[4] = 934 632 entry_size[5] = 945 633 entry_size[6] = 948 634 entry_size[7] = 956 635 entry_size[8] = 955 636 entry_size[9] = 930 637 entry_size[10] = 933 638 entry_size[11] = 934 639 entry_size[12] = 972 640 entry_size[13] = 977 641 entry_size[14] = 958 642 entry_size[15] = 949 643 entry_size[16] = 962 644 entry_size[17] = 848 645 [stco: Chunk Offset Box] 646 position = 703 647 size = 24 648 version = 0 649 flags = 0x000000 650 entry_count = 2 651 chunk_offset[0] = 797 652 chunk_offset[1] = 13096 653 [sgpd: Sample Group Description Box] 654 position = 727 655 size = 26 656 version = 1 657 flags = 0x000000 658 grouping_type = roll 659 default_length = 2 (constant) 660 entry_count = 1 661 roll_distance[0] = -2 662 [sbgp: Sample to Group Box] 663 position = 753 664 size = 28 665 version = 0 666 flags = 0x000000 667 grouping_type = roll 668 entry_count = 1 669 entry[0] 670 sample_count = 18 671 group_description_index = 1 672 [free: Free Space Box] 673 position = 781 674 size = 8 675 [mdat: Media Data Box] 676 position = 789 677 size = 17001 678<a name="5"></a> 6795 Authors' Address 680 Yusuke Nakamura 681 Email: muken.the.vfrmaniac |at| gmail.com 682 </div> 683 </body> 684</html> 685